1. Field of the Invention
The invention relates to a computer network and a process for linking computers and/or sets of computers in a networking system.
2. Description of the Related Technology
"DATACOM" 1988, No. 3, pages 81 to 87, discloses networking methods for linking local networks of computers. Bridges are used in local networks according to the IEEE 802.3 standard or the Ethernet standard, as linking circuits. When a bridge or line fails or is interrupted in a network system and the other bridges analyze the target and source addresses a bridge may recognize the failure or interrupt and take over the data transmission. The bridges are also able to determine when an initially failed bridge has resumed operation based on target and source analysis. This signifies that a ring connection has appeared within the network system, which may lead to faults. Following the detection of a ring connection, the bridges are able to dissolve it.
FIG. 1 schematically shows a networking system using local bridges of this type. The network segments 1, 2 and 3 comprising the individual computers are connected with each other by the local bridges 4, 5 and 6. In case of the failure of one of the local bridges 4, 5 or 6 or one of the lines associated with them, the remaining bridges take over the transmission of data, so that data transmission is assured in the network system even if a line has failed. Following the reestablishment of the line connection involved, a ring connection may be present over local bridges 4, 5 and 6. Ring connections may lead to race situations and must be eliminated. In view of their extensive and complicated circuit technology, the bridges are capable of detecting such a ring connection and interrupting the ring transport. For example, data may be transmitted from the network segment 1 over only one connecting path. Only local bridge 4 and not bridges 5 and 6 is utilized to transmit data from segment 1. The use of such local bridges is often not suitable or desirable in view of their high hardware and software costs and in particular in the layout of smaller network systems
FIG. 2 shows another known embodiment of a network system. FIG. 2 shows an optical network based on beam waveguides. Active star coupling connectors 21, 22, 23 and 24 are used to connect the parties. The star couplers 21, 22, 23 and 24 are connected by beam waveguides to adjacent star couplers, as indicated by the lines 25, 26 and 27.. Empty or IDLE signals are transmitted on the connecting lines between data signals or packets in order to monitor the line. The data may be transmitted over a redundant path 28 in case of outage of an IDLE signal as the result of an interruption of the connecting lines 25 or 27, in the star connector 21 or 24. Even during an interruption, the network system will operate in a regular manner.
The use of redundant paths in network systems for redundant transmission of data in case of failure of a connecting line or star connector is limited and not sufficient in point-to point connections or connections with only one star connector located between two other star connectors.
If the connecting line 26 fails between the star connectors 22 and 23, the presence of a redundant path 28 cannot compensate this fault, as the star connectors 21 and 24 cannot detect the failure and will not switch through the redundant path 28.